Abstract
BACKGROUND: For young borderline ovarian tumor (BOT) patients, preservation of the uterus was incorporated as an accepted option into treatment guidelines. For the endometrioid subtype (eBOT) however, adequate histological evaluation is challenging and might be associated with synchronous endometrial disorders or misinterpreted as spread from uterine primaries. CASE PRESENTATION: We report the cases of two young patients with eBOT who underwent treatment according to current guidelines. In both cases, unexpected findings of invasive uterine carcinomas were established in final histopathological evaluation. CONCLUSIONS: This constellation highlights the challenging diagnostic workup of BOT and underlines that uterine curettage is indispensable for eBOT to exclude uterine primary tumors when fertility preservation is planned. Accordingly, we suggest to include this procedure into recommendations for diagnostic workup and to state the potential risk in treatment guidelines.